[Pyogenic abscess of the psoas]

11 cases (7 primary and 4 secondary) of pyogenic psoas abscesses are reported. In all cases Staphylococcus aureus was isolated on blood culture or pus drained under ultra-sonographic control. US is very useful for diagnosis and the follow up of psoas pyogenic abscesses. Percutaneous aspiration and drainage of psoas abscesses under ultrasonographic control combined to antibiotherapy is an effective therapeutic procedure. Our experience suggests that antibiotherapy alone is an effective therapy of presuppurative pyogenic psoas abscesses and even in collected and non complicated primary psoas abscesses.